Acetyl cellulose



Fatented lien 8, i923.

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.ACETYL CELLULOS E.

No Drawing. a 7

Application filed August12, 1919. Serial No. 317,081.

(GRANTED UNDER THE PROVISIONS OF THE ACT GF MARCH 3, i921, 4:1 STAT. L., 1318.)

To (171 whom, it may concern:

it known that I, WALTER James STE- vnNsoN, a sub ect of the King of Great Britain, residing at Charing Cross Hotel, Char- .5 ing (moss, in the county ot' London, England, have invented certain new' and useful Improvements in A cetyl Cellulose (for which I have made-application in Great BritainNov. 30, 1917, Patent No. 130,029),

10 of Which the following is a specification.

This invention relates to the manufacture of acetyl cellulose.

Hitherto the basic material employed for the manufacture of acetyl cellulose has been bleached cotton Wool.

According to the present invention bleached sulphite paper pulp is employed as thebasic material instead of bleached cotton wool. This gives me greater stability, more homogeneous control, greater or larger life,

and better ability to take all dyes or colors than acetyl cellulose from cotton, cotton waste, or wood pulp, used as a basic material for making acetyl cellulose. Bleached sulphite paper pulp is a much cheaper material thanblcaehed cottonuvool. As catalyzers zincchloride, or nitric acid, or dimethyl sulphate may be employed.

I As an'example of the method of carrying the invention into effect the materials" may be taken in the following proportions.

" lilcached sulphite paper vpulp l kilogramme Glacial acetic ac1d 4.0 liilogran'ime Acet1canhydr1dc 2.8 kilogramme Zinc chloride 200 grammes '120 degreescentigrade. The precipitate is easily'dissolved in pure dry acetone to form a transparent solution. By the use of concentration and recovery plant from seventyfive to eighty per cent of the waste acid may be recovered.

As alternative catalysts to-the zinc chlo ride nitric acid or di methyl sulphate may be employed in the same proportion.

lVhat-I claim and desire to secure by Letters Patent ot' the United States is 1. A method of manufacturing 'acetyl cellulose which consists in acetylating bleached sulphite paper pulp in the presence of a catalyst.

2. The manufacture of acetyl cellulose by mixing bleached sulphite paper pulp, glacial a 0 o acetic acid, acetic anhydride and zinc chloride.

3. The manufacture of acetyl cellulose by mixing the following materials substantially in the following proportions:

4. Acetyl celluloseproduced by acetylatlug bleached sulphite paper pulp.

WALTER J AMES STEVENSON. 

